The present invention relates generally to operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides an explosive system for casing damage repair.
Casing damage presents several distinct problems. This is particularly so where the casing has been damaged in such a way that access therethrough is limited. In these situations, access through the damaged casing must typically be restored before remedial measures, such as installation of a casing patch or an expandable casing liner, may be taken.
Unfortunately, methods of restoring access through damaged casing have proven inadequate in many circumstances, such as when the casing has become xe2x80x9cdogleggedxe2x80x9d or longitudinally compressed due to subsidence. Thus, it may be seen that it would be advantageous to provide systems and methods for repairing damaged casing which include the capability of restoring access through the damaged casing. Of course, these systems and methods would prove beneficial in other operations, as well.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, an explosive system and associated method are provided which solve the above problems in the art in a convenient and efficient manner which produces superior results.
In one aspect of the invention, an explosive system is provided which includes a liquid explosive disposed within a flexible elongated tubular container. The flexible container and the liquid nature of the explosive permit the explosive system to be conveniently positioned within damaged casing which might be otherwise inaccessible to rigid explosive assemblies.
The explosive system may include any of a variety of features including a specially configured upper housing for filling the container with the liquid explosive, a specially configured lower plug for retaining the liquid explosive in the container, weight material in the plug for situations in which the explosive system would otherwise be buoyant in fluid present in the wellbore, a specially configured fluid retainer which permits venting of the liquid explosive from the container, etc.
In addition, the explosive system may be conveyed into the wellbore using any of a variety of conveyances, such as a tubing or drill string, a wireline, a slickline, etc. Furthermore, the liquid explosive may be detonated using any of a variety of detonating means, such as a firing head attached to a tubing string, a detonator electrically connected to a line extending to a remote location, etc.
In another aspect of the present invention, a method is provided for repairing damaged casing in a wellbore. The method includes the steps of conveying a liquid explosive into the wellbore, positioning the liquid explosive within the damaged casing and detonating the liquid explosive. The liquid explosive may be conveyed into the wellbore using a container, such as the flexible tubular container discussed above, or the liquid explosive may be flowed into the wellbore, for example, through a tubing string.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings.